License plate readers are now in use across most U.S. states, but the rules about how they work and what happens to the data vary widely

License plate readers (LPRs) are cameras that automatically capture and record vehicle registration numbers as cars pass by. They are mounted on police vehicles, fixed at intersections, on highways, and at parking facilities. The technology exists in at least 40 states, though the exact number changes as departments add or remove systems. What matters more than the count is what each state allows: some states have strict rules about data storage and use, while others have almost none.

The core function is the same everywhere: the camera reads the plate, the system records the time and location, and that data is stored in a database. But whether police can keep that data for months, whether they can share it with other agencies, whether the public can request records, and whether you get notified if your plate is flagged—those answers depend entirely on state law and local policy.

Key Takeaways

  • License plate readers operate in at least 40 states, but state laws differ sharply on how long data can be kept and who can access it.
  • Some states like California and Vermont have passed laws limiting data retention to 30 days or requiring a warrant before police can search the database.
  • Other states have no statewide rules, leaving individual police departments to set their own data policies.
  • Data from readers is often shared between agencies and sometimes sold to private companies, which is legal in most states unless local law forbids it.
  • You can contact your state's attorney general or local police department to learn what rules explore where you live.

States with the strictest data rules

California was one of the first states to pass a law limiting how long police can keep license plate reader data. Under California law, data must be deleted within 30 days unless it is connected to a specific investigation. Police cannot search the database just to see where a car has been; they need a reason tied to a crime or a missing person. The law also requires that any data shared with other agencies follow the same 30-day rule.

Vermont passed similar rules requiring deletion within 30 days and forbidding searches without a warrant or connection to an investigation. New Hampshire limits retention to 60 days. These states treat the data more like evidence than like a general surveillance tool, which means the database cannot be used to track people's movements over time just because police are curious.

A handful of other states—including Illinois, Maine, and Washington—have passed laws requiring a warrant or court order before police can search the database, or they limit how the data can be used. The specifics vary: some states allow searches only for stolen vehicles or wanted suspects, while others are stricter. Contact your state's attorney general office to find out what the actual rule is in your state, because the law may have changed recently.

States with minimal or no statewide rules

Most states have no statewide law governing license plate readers at all. This means individual police departments, sheriff's offices, and highway patrol agencies can decide for themselves how long to keep the data, who can access it, and whether to share it with other agencies or private companies. In these states, the rules might differ between the city police and the county sheriff, or between one county and the next.

In states without statewide rules, data is often kept for months or years. Some departments share access with federal agencies like the FBI and ICE. Private companies that operate license plate reader networks—such as Vigilant Solutions (now owned by Motorola)—collect data from police cameras and sell access to law enforcement, which means your plate data can be searched by agencies far from where you live. None of this is illegal in most states; it is straightforward unregulated.

If you live in a state without statewide rules, your only recourse is to contact your local police department or city council and ask what their policy is. Some departments have adopted their own retention limits or warrant requirements even when the state does not require it. Others have not.

How data is collected and stored

License plate readers work passively: they photograph every plate that passes by, not just the ones police are looking for. A single reader can capture thousands of plates per day. The system stores the plate number, the date, the time, and the GPS location. Over time, this creates a detailed record of where vehicles have been.

The data is stored in a database that police can search. In states with strict rules, officers must have a specific reason to search—a stolen car, a wanted suspect, a missing person. In states with no rules, officers can search for any reason or no reason at all. Some departments use the data reactively (searching after a crime) and some use it proactively (searching to see where a car has been over weeks or months).

The data is often shared between agencies. A local police department might share access with the state highway patrol, the FBI, or federal immigration enforcement. In some cases, data is sold to private companies that resell access to other law enforcement agencies. This means a plate reading in one state can be searched by police in another state, and you may never know it happened.

What to do if you want to know your state's rules

Start by contacting your state's attorney general office. Their website usually has a summary of state privacy laws, or you can call and ask whether your state has a license plate reader law. If your state does have a law, the attorney general's office can tell you what it says and which agencies it applies to.

If your state has no statewide law, contact your local police department or city council. Ask whether they have a policy on license plate reader data retention, whether they share data with other agencies, and whether they use private companies like Vigilant Solutions. Some departments will answer; others will not. If your city council has a public records request process, you can file a request for the department's license plate reader policy.

You can also check whether your state has a pending bill on this topic. Organizations like the Electronic Frontier Foundation (EFF) track license plate reader legislation state by state. If your state is considering new rules, you can contact your state representative or senator to express your view.

The difference between public and private readers

Police-operated readers are the most common, but private companies also use the technology. Parking lots, toll roads, and private security companies operate readers that capture plate data. In most states, private readers are not regulated at all—the company can keep the data as long as it wants and share it with anyone. Private data is sometimes sold to law enforcement, which means a parking lot reader can end up in a police database.

Some states have begun to regulate private readers. California's law, for example, applies to both police and private operators. But most states have no rules about private readers. If you are concerned about your privacy, this is a gap worth knowing about: a reader at a parking lot or toll road may be collecting your data with no oversight.

Federal use of license plate reader data

Federal agencies like the FBI, ICE, and the DEA can access license plate reader data from local police departments in most states. In some cases, federal agencies operate their own readers or buy access to private databases. There is no federal law that limits how long federal agencies can keep the data or how they can use it, though some states' laws do not explore to federal use.

This means that even if you live in a state with strict rules, federal agents may be able to search your plate data under different rules or no rules at all. The relationship between state law and federal access is complicated and varies by state. If you are concerned about federal access, contact your state's attorney general or a civil rights organization like the ACLU for information specific to your state.

Frequently Asked Questions

Can I learn about my license plate has been scanned?

In most states, no. You have no automatic right to know when or where your plate was read. Some states allow you to file a public records request asking for all scans of your plate, but the police department may refuse if they say it would interfere with an investigation. California and a few other states have stronger transparency rules, but even there, getting the data can take months.

Do I have to do anything if I live in a state with license plate readers?

No action is required. The readers work automatically and you cannot opt out. If you want to know what rules explore where you live, contact your state attorney general or local police department. If you want to push for stricter rules, you can contact your state representative or support organizations working on license plate reader privacy laws.

Can police use license plate reader data to track where I go?

It depends on your state. In states like California and Vermont, police need a warrant or a specific investigation reason to search the database, which limits tracking. In states with no rules, police can search the database for any reason or no reason. Even in strict states, federal agents may have different rules. Check your state's law to understand what is allowed.

What happens if my plate is flagged by a license plate reader?

If your plate matches a stolen vehicle alert or a wanted person alert, police may stop you. If your plate is flagged for another reason—such as an outstanding warrant or a traffic violation—the outcome depends on the reason. You have the same rights during any traffic stop, including the right to ask why you were stopped and to refuse searches without a warrant.

Is license plate reader data the same as traffic camera footage?

No. Traffic cameras record video of intersections and are used to catch red-light violations or document accidents. License plate readers are automated systems that record only the plate number, date, time, and location. Traffic camera footage is usually kept for a short time and then deleted. License plate reader data is stored in a searchable database and kept much longer.